Company lists · Data refreshed September 2026

Top 25 Energy efficiency companies worldwide

RevenueBase identified 11,307 energy efficiency companies worldwide as of September 2026 and tracks 142,018 professional contacts across them, including 49,865 with verified work emails and 0 with mobile numbers. The United States is the largest market and Madrid the largest hub.

This list covers energy efficiency companies worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 15, 2026. Country and city lists for energy efficiency companies follow the table.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 15, 2026 86% judged on-target in blind review
11,307Companies
142,018Contacts tracked
49,865Verified emails
0Mobile numbers
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The 25 largest energy efficiency companies worldwide

Ranked by team size
Top 25 of 11,307 energy efficiency companies worldwide, ranked by team size, largest first. Data refreshed Sep 15, 2026. RevenueBase Smart Search rates how each company's information relates to energy efficiency companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceWindsor, United KingdomHQ checked Sep 15, 202610001+9,238 contacts →

Indirect evidence

“Taking care of things.”

Source: RevenueBase Database · checked Sep 15, 2026
2Indirect evidenceSaint-andré-lez-lille, FranceHQ checked Sep 15, 202610001+8,427 contacts →

Indirect evidence

“Dalkia : ensemble, relevons le défi climatique!”

Source: RevenueBase Database · checked Sep 15, 2026
3Partial evidenceDubai, United Arab EmiratesHQ checked Sep 15, 20265,001-10,0004,058 contacts →

Partial evidence

“Enova is the regional leader in integrated energy and multi-technical services, delivering comprehensive services to its clients.”

Source: RevenueBase Database · checked Sep 15, 2026
4Strong evidenceLondon, United KingdomHQ checked Sep 15, 20261,001-5,0002,627 contacts →

Strong evidence

“We help businesses manage energy needs, boost efficiency, control costs and achieve decarbonisation goals for a better energy future.”

Source: RevenueBase Database · checked Sep 15, 2026
5Partial evidenceSeattle, WA, United StatesHQ checked Sep 15, 20261,001-5,0002,213 contacts →

Partial evidence

“We're a national construction and energy services company dedicated to innovating the waste and climate harm out of the built environment.”

Source: RevenueBase Database · checked Sep 15, 2026
6Strong evidenceAustin, TX, United StatesHQ checked Sep 15, 20261,001-5,0002,121 contacts →

Strong evidence

“CLEAResult is the largest provider of energy efficiency, energy transition and energy sustainability services in North America.”

Source: RevenueBase Database · checked Sep 15, 2026
7Partial evidenceFramingham, MA, United StatesHQ checked Sep 15, 20261,001-5,0001,383 contacts →

Partial evidence

“Ameresco, Inc.(NYSE:AMRC) is a leading energy infrastructure solutions provider dedicated to helping customers reduce costs, enhance resilience, and decarbonize to net zero in the…”

Source: RevenueBase Database · checked Sep 15, 2026
8Indirect evidenceOslo, NorwayHQ checked Sep 15, 20261,001-5,0001,150 contacts →

Indirect evidence

“GK er en ledende teknisk entreprenør og servicepartner.”

Source: RevenueBase Database · checked Sep 15, 2026
9Strong evidenceNordborg, DenmarkHQ checked Sep 15, 202610001+1,128 contacts →

Strong evidence

“At Danfoss Climate Solutions, we engineer energy-efficient heating and cooling solutions to help the world get more out of less.”

Source: RevenueBase Database · checked Sep 15, 2026
10Partial evidenceEschborn, GermanyHQ checked Sep 15, 20261,001-5,0001,021 contacts →

Partial evidence

“Techem is a leading global energy service provider for the real estate sector and private homeowners.”

Source: RevenueBase Database · checked Sep 15, 2026
11Indirect evidenceAnaheim, CA, United StatesHQ checked Sep 15, 20261,001-5,000851 contacts →

Indirect evidence

“Willdan (NASDAQ: WLDN) provides professional consulting and technical services to utilities, public agencies and private industry throughout the United States.”

Source: RevenueBase Database · checked Sep 15, 2026
12Partial evidenceOakland, CA, United StatesHQ checked Sep 15, 2026201-500772 contacts →

Partial evidence

“Our mission is simple - to combat climate change through market-based, cost-effective energy, carbon, and water management solutions that make big impacts.”

Source: RevenueBase Database · checked Sep 15, 2026
13Partial evidenceHalf Moon Bay, CA, United StatesHQ checked Sep 15, 2026501-1,000733 contacts →

Partial evidence

“Resource Innovations (RI) is an energy transformation firm.”

Source: RevenueBase Database · checked Sep 15, 2026
14Partial evidenceEdison, NJ, United StatesHQ checked Sep 15, 20261,001-5,000669 contacts →

Partial evidence

“Albireo Energy is a leading independent building controls and energy services provider recognized by customers for creating intelligent, high-performance buildings.”

Source: RevenueBase Database · checked Sep 15, 2026
15Indirect evidenceMilan, ItalyHQ checked Sep 15, 2026201-500608 contacts →

Indirect evidence

“Da dicembre 2025, abbiamo integrato EF Solare, il primo produttore fotovoltaico italiano.”

Source: RevenueBase Database · checked Sep 15, 2026
16Partial evidenceWestborough, MA, United StatesHQ checked Sep 15, 2026201-500481 contacts →

Partial evidence

“NORESCO, a part of Carrier Global Corporation, helps customers modernize aging building systems and upgrade energy and water infrastructure to meet evolving demands.”

Source: RevenueBase Database · checked Sep 15, 2026
17Partial evidenceGurugram, IndiaHQ checked Sep 15, 2026201-500470 contacts →

Partial evidence

“Serentica Renewables India Private Limited,(Serentica) is a is an end-to-end energy solutions company enabling large-scale heavy energy intensive industries and sector to…”

Source: RevenueBase Database · checked Sep 15, 2026
18Partial evidenceAubervilliers, FranceHQ checked Sep 15, 20261,001-5,000460 contacts →

Partial evidence

“Veolia Industries Global Solutions est devenu Veolia Energie Performance depuis le 1er juin 2025.”

Source: RevenueBase Database · checked Sep 15, 2026
19Indirect evidenceNoisy-le-grand, FranceHQ checked Sep 15, 2026501-1,000452 contacts →

Indirect evidence

“Pour une énergie propre et mieux utilisée Notre mission : fournir des solutions énergétiques performantes et économiques, tout en minimisant l'impact environnemental.”

Source: RevenueBase Database · checked Sep 15, 2026
20Partial evidencePhoenix, MO, United StatesHQ checked Sep 15, 2026501-1,000383 contacts →

Partial evidence

“Veregy is an award-winning NAESCO-Accredited decarbonization company focusing on accelerating and simplifying the Energy Transition.”

Source: RevenueBase Database · checked Sep 15, 2026
21Partial evidenceIrvine, CA, United StatesHQ checked Sep 15, 2026201-500383 contacts →

Partial evidence

“We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.”

Source: RevenueBase Database · checked Sep 15, 2026
22Strong evidenceShelton, CT, United StatesHQ checked Sep 15, 2026201-500366 contacts →

Strong evidence

“Budderfly is redefining how energy efficiency, resilience, and grid participation can work together across America’s commercial sector.”

Source: RevenueBase Database · checked Sep 15, 2026
23Partial evidenceToronto, ON, CanadaHQ checked Sep 15, 2026201-500363 contacts →

Partial evidence

“Since 1964 the MCW Group has built a solid reputation for the delivery of Professional Consulting Engineering Services, Energy Management Services, and Engineering Development…”

Source: RevenueBase Database · checked Sep 15, 2026
24Strong evidenceMedford, MA, United StatesHQ checked Sep 15, 2026201-500356 contacts →

Strong evidence

“At HomeWorks Energy, our mission is simple, literally: Energy Efficiency, Simplified.”

Source: RevenueBase Database · checked Sep 15, 2026
25Strong evidenceWilliamsville, NY, United StatesHQ checked Sep 15, 2026201-500355 contacts →

Strong evidence

“Wendel is an Architecture, Engineering, Energy Efficiency, and Construction Management Firm that delivers customized solutions and turnkey projects in innovative ways.”

Source: RevenueBase Database · checked Sep 15, 2026

Showing 25 of 11,307 energy efficiency companies worldwide

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Energy efficiency companies worldwide at a glance

As of Sep 15, 2026
35.1%Verified-email coverage
12.6Average contacts per company
1-10Median size (employees)
1.5%Largest-city concentration · Madrid
Sep 15, 2026Page data refreshed

Companies by employee count

1-10
6,573
11-50
3,566
51-200
855
201-500
156
501-1,000
39
1,001-5,000
38
5,001-10,000
5
10001+
9

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among energy efficiency companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
Coverage
36 countries, largest first: the United States, France, Italy, Spain, the United Kingdom, Germany, Brazil, Canada, Australia, the Netherlands and 26 more. Country and city lists for energy efficiency companies are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “energy efficiency companies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names energy efficiency companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among energy efficiency companies, and records with no verified work email.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 49,865 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 15, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Energy efficiency companies by location

51 lists · largest first

Every Energy efficiency companies list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names energy efficiency companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many energy efficiency companies are there worldwide?

RevenueBase identified 11,307 energy efficiency companies worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

British GAS, headquartered in Windsor, tops this list with the largest team on record.

Which country has the most energy efficiency companies?

The United States leads with 2,440 companies, followed by France (1,084) and Italy (980). Every energy efficiency companies list by country and city is linked on this page.

Which city has the most energy efficiency companies?

Madrid leads with 165 headquartered companies, followed by Paris (150) and London (123).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 49,865 verified decision-maker contacts tracked across these 11,307 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 15, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.